Problems with equipment port flanges
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For the selection of pipe short-circuit flanges for high-voltage equipment, male-and-female flat flanges are commonly used. So, should a concave flange or a convex flange be used on the side closest to the equipment? Why? Are there any mandatory requirements? Last edited by sister on 2009-2-6 01:16]
Concave flanges are generally used on the equipment
It is mainly to prevent the sealing surfaces from being damaged during transportation of the equipment.
http://bbs.hcbbs.com/viewthread.php?tid=211251&highlight=%B0%BC%CD%B9%C3%E6%B7%A8%C0%BC You can take a look at this post
It’s not a general topic; here it specifically refers to high-pressure raised and recessed face flanges, not ordinary flat flanges.
The equipment should have a concave flange to facilitate transportation and disassembly
It is specified in HG20583-1998 \"Code for Structural Design of Steel Chemical Vessels\".
The device should have a concave flange, mainly to make it easier to place gaskets
For most equipment, concave flanges are chosen; when connecting safety valves and level gauges, the issue of matching also needs to be taken into account
A concave flange is used on the side of the equipment that is close to it, as during the manufacturing process the equipment often has to be turned over multiple times for welding purposes; this inevitably leads to the flange coming into contact with or even colliding with the floor or other hard surfaces. To ensure good sealing performance and protect the sealing surface, concave flanges are generally used. Additionally, they help prevent damage during transportation.
First, let’s discuss a question with my sister: Can concave-convex flanges be used for the nozzles of high-pressure vessels? :Funk: By the criteria for pressure ratings, high pressure refers to a pressure of >=10.0 MPa; in my opinion, such conditions make it unsuitable for use. :o Answering general questions: The pipe connection flanges on equipment are usually concave. This post was last edited by rgsmdqy on 2009-2-5 00:37]
Consider using shims; the upward-facing side is concave, while the downward-facing side is convex
According to the Regulations for Structural Design of Steel Chemical Vessels, concave flanges should be installed on the pipe openings at the top and sides of the vessel, while convex flanges should be installed on the pipe openings at the bottom of the vessel.
For the convenience of fitting gaskets, except for those with the pipe end facing downward which are convex, they are all concave. However, according to Appendix A of HG20592-97 \"Selection of Seal Surface Types\", when used with valves having a PN of 4.0 MPa or higher, the integral flange on the valve is generally concave, while the seal surface of the pipe flange should be convex. The main consideration is the availability of valves.
Is it solved? The question raised by the Peach Wood Super Edition wasn’t discussed any further!
Concave-convex flanges are used for designs where the pressure is ≤6.4 MPa and DN ≤800; concave flanges are used for pipe end flanges, while convex flanges are used for manholes.
Concave flanges are commonly used on the upper and side parts of the equipment, while convex flanges are typically used on the lower part, in order to protect the gaskets and to facilitate their installation
I’m not an expert in equipment, so I’m not quite sure how high voltage, medium voltage, and low voltage are classified. Please help me understand! What I mean is pressure vessels with a pressure of around 1 MPa; I’ve seen quite a few with a concave surface. But when they are connected directly to valves, which also have a concave surface, it’s confusing. Of course, it seems that a direct connection does not meet the specifications; a short circuit should be added. But sometimes, having one fewer connection means there is one fewer point of leakage. I’m not sure if I made myself clear……
“What does “convex surface for manholes” mean? Could you explain it more clearly?